Subluxación atlantoaxial en artritis reumatoidea. Resolución por odontoidectomía endonasal endoscópica y fusión e instrumentación por abordaje posterior. Reporte de caso

La subluxación atlantoaxial es la lesión más frecuente en la columna cervical causada por la artritis reumatoidea. Se manifiesta por rigidez de nuca, dolor cervical y déficit neurológico. El diagnóstico se realiza con tomografía computarizada e imágenes de resonancia magnética. El intervalo atlanto dental anterior mayor a 5mm indica inestabilidad atlantoaxial, el intervalo atlanto dental posterior menor a 14mm advierte riesgo neurológico. Las indicaciones más frecuentes de cirugía son: dolor cervical severo, inestabilidad y síntomas de mielopatía. Cuando existe compresión medular es necesaria la descompresión cervical alta sea por vía posterior o por vía anterior (odontoidectomía endonasal versus transoral). La línea rinopalatina nos indicará la factibilidad de una odontoidectomía endonasal endoscópica (OEE). El objetivo de la presentación del presente caso es compartir nuestra experiencia con la primera odontoidectomía endonasal endoscópica realizada en nuestro país y fomentar la utilización de la técnica. La cirugía fue realizada en un paciente con cuadriparesia espástica por subluxación atlantoaxial por artritis reumatoidea y que presentó excelente evolución pos operatoria, con recuperación casi completa. La OEE es una técnica operatoria mínimamente invasiva, ideal para pacientes con múltiples comorbilidades y que ofrece de buenos a excelentes resultados.

Atlantoaxial subluxation is the most common injury to the cervical spine caused by rheumatoid arthritis. It is manifested by neck stiffness, neck pain and neurological deficit. Diagnosis is made with computed tomography and magnetic resonance imaging. The anterior dental atlanto interval greater than 5mm indicates atlantoaxial instability, the posterior dental atlanto interval less than 14mm warns of neurological risk. The most frequent indications for surgery are: severe neck pain, instability and symptoms of myelopathy. When there is spinal cord compression, upper cervical decompression is necessary, either via a posterior or anterior approach (endonasal versus transoral odontoidectomy). The rhinopalatine line will indicate the feasibility of an endoscopic endonasal odontoidectomy (EEO). The objective of the presentation of this case is to share our experience with the first endoscopic endonasal odontoidectomy performed in our country and to promote the use of the technique. The surgery was performed on a patient with spastic quadriparesis due to atlantoaxial subluxation due to rheumatoid arthritis and who presented excellent postoperative evolution, with almost complete recovery. EEO is a minimally invasive surgical technique, ideal for patients with multiple comorbidities and offering good to excellent results.

Three-dimensional finite element analysis of a new horizontal screw-screw crosslink in posterior atlantoaxial internal fixation / 中国组织工程研究

BACKGROUND:The addition of traditional rod-rod fixation for atlantoaxial joint disease to C1-C2 pedicle screw-rod fixation(C1-C2 PSR)can provide stronger anti-rotation stability for screw/rod fixation,but there is a risk of installation difficulties,impact on bone graft bed,and spinal cord injury.The new horizontal screw-screw crosslink(hS-S CL)designed by the authors can effectively overcome the above shortcomings,but its biomechanical properties are unclear. OBJECTIVE:To analyze biomechanical properties of new horizontal screw-screw crosslink in C1-C2 PSR by three-dimensional finite element analysis. METHODS:CT thin layer scanning data were collected from the occipital base to the axis(C0-2)of one adult healthy male volunteer.The atlantoaxial finite element models were established respectively:the normal group,the unstable group,the non-crosslink group(unstable+C1-C2 PSR),and the crosslink group(C1-C2 PSR+hS-S CL).Range of motion and Von Miss Stresses in flexion and extension,lateral flexion and rotation of the four groups were calculated by applying 1.5 Nm torque to each finite element model,and the stress cloud was extracted. RESULTS AND CONCLUSION:(1)Range of motion of the unstable group was increased by 43.8%-78.7%compared with the normal group,and the range of motion of the internal fixation groups was 90.2%-98.7%lower than that of the unstable group under six conditions.The range of motion of the crosslink group and the non-crosslink group was basically the same in flexion and extension states,but in lateral flexion and rotation states,the range of motion of the crosslink group decreased 34.3%-43.8%and 78.6%-79.1%,respectively,compared with the non-crosslink group,and range of motion decreased most obviously in rotation state.(2)The stress peak of the internal plant model:The maximum stress of the crosslink group was generally smaller than that of the non-crosslink group,and the stress peak value of all the internal fixation groups was the lowest when the extension was carried out.(3)The stress cloud of internal plants showed that there was no obvious stress concentration phenomenon in the internal fixation,and the main stress distribution areas were the screw root and bone joint,and the crosslink ends were the screw tail groove or the joint rod joint.(4)The new horizontal screw-screw crosslink can obviously improve the anti-rotation stability of internal fixation and it can share part of the pressure in the three-dimensional motion direction of the internal fixation system and reduce the maximum stress of the internal plants.However,the stress distribution is obvious at both ends of the crosslink,and this part may be prone to fracture of the crosslink.

Biomechanical analysis of new horizontal screw-screw crosslink in C1-C2 pedicle screw-rod fixation / 中国组织工程研究

BACKGROUND:Posterior atlantoaxial pedicle screw rod internal fixation is the main method for treating atlantoaxial dislocation,and the horizontal crosslink plays an important role in the antirotation ability of the internal fixation system.The new horizontal screw-screw crosslink can effectively overcome the disadvantages of traditional horizontal crosslink,such as inconvenient installation,impact on bone grafting bed,and potential spinal cord injury.However,the biomechanical properties of the new horizontal screw-screw crosslink with different installation modes are still unclear. OBJECTIVE:To investigate the biomechanical characteristics of new different installation modes of horizontal screw-screw crosslink in the C1-C2 pedicle screw-rod fixation and to provide a theoretical basis for optimal installation mode. METHODS:Six fresh human occipitocervical specimens were divided into the intact state group(group A),and the atlantoaxial instability model of type Ⅱ odontoid fracture was established based on the intact state group as the instability group(group B).The C1-C2 pedicle screw-rod fixation was performed on each specimen based on the instability group(group C).In group C,different installation modes of horizontal screw-screw crosslink were successively installed in each specimen,including upper transverse connection(two atlas screw tails)as group D,lower transverse connection(two axis screw tails)as group E,diagonal transverse connection(upper left and lower right for group F,lower left and upper right for group G),and cross transverse connection as group H.The specimen models were tested in order of flexion,extension,lateral flexion and lateral rotation on a three-dimensional motion machine,and the atlantoaxial range of motion of each group of specimens was obtained.Repeated measure analysis of variance was used to evaluate the biomechanical properties of each group. RESULTS AND CONCLUSION:(1)Under six states,the range of motion of groups A,C,D,E,F,G and H was smaller than that of group B,and there were statistically significant differences(P＜0.05).(2)In the flexion and extension states,there was no significant difference among the five types of horizontal screw-screw crosslink groups(P＞0.05).(3)In the left and right rotation directions,there were significant differences in D and E groups compared with F,G and H groups(P＜0.05);there were no significant differences between D and E groups,and F and G groups(P＞0.05),and there were no significant differences in F and G groups compared with H group(P＞0.05).(4)In conclusion,under flexion-extension states,the biomechanical stability of five types of horizontal screw-screw crosslink groups was similar,but under the rotation state,the stability of diagonal horizontal screw-screw crosslink group and cross horizontal screw-screw crosslink group was obviously better than that of transverse horizontal screw-screw crosslink group;however,the stability of diagonal horizontal screw-screw crosslink group is similar to the cross horizontal screw-screw crosslink group,so the former is more worthy of clinical recommendation.

Meta-analysis of the incidence and related factors for cervical spine instability in patients with rheumatoid arthritis / 中国组织工程研究

OBJECTIVE:At present,there are many reports on the related factors associated with the incidence of cervical spine instability in patients with rheumatoid arthritis,but there are problems such as small sample size and many confounding factors,and the research results of various studies on the same related factors are also different.This article analyzed the factors related to cervical spine instability in patients with rheumatoid arthritis by means of a systematic review. METHODS:Articles related to cervical spine instability in patients with rheumatoid arthritis were collected by searching both Chinese and English databases until March 2023.The outcome of cervical spine instability in patients with rheumatoid arthritis was used as the grouping criterion to abstract basic information,baseline patient characteristics,laboratory-related tests,medication use,and other relevant risk factors.Meta-analysis was done using Stata 14.0 software. RESULTS:(1)Sixteen relevant studies,all of moderate or above quality,were included,including seven studies with case-control studies and nine with cross-sectional studies.The overall incidence of cervical spine instability in patients with rheumatoid arthritis was 43.08%.(2)Meta-analysis showed:Related risk factors included female(OR=0.60,95%CI:0.44-0.82,P=0.002);age at disease onset(SMD=-0.52,95%CI:-0.86 to-0.18,P=0.003);duration of disease(SMD=0.58,95%CI:0.14-1.02,P=0.01);body mass index(OR=0.74,95%CI:0.63-0.88,P=0.001);rheumatoid factors positive univariate analysis subgroup(OR=1.33,95%CI:1.02 to 1.72,P=0.04),C-reactive protein(SMD=0.26,95%CI:0.16-0.35,P=0.00),erythrocyte sedimentation rate(SMD=0.15,95%CI:0.002-0.29,P=0.047),anti-cyclic-citrullinated peptide antibodies(OR=1.73,95%CI:1.19-2.51,P=0.004),28-joint Disease Activity Score(SMD=0.20,95%CI:0.04-0.37,P=0.02),destruction of peripheral joints(OR=2.48,95%CI:1.60-3.85,P=0.00),and corticosteroids(OR=1.91,95%CI:1.54-2.37,P=0.00)were strongly associated with the development of rheumatoid arthritis-cervical spine instability.Female and corticosteroid use were independently associated with the occurrence of rheumatoid arthritis-cervical spine instability. CONCLUSION:Based on clinical evidence from 16 observational studies,the overall incidence of rheumatoid arthritis-cervical spine instability was 43.08%.However,the incidence of cervical spine instability in rheumatoid arthritis patients varied greatly among different studies.Gender(female)and the use of corticosteroids were confirmed as independent correlation factors for the onset of cervical spine instability in patients with rheumatoid arthritis.The results of this study still provide some guidance for early clinical recognition,diagnosis,and prevention of rheumatoid arthritis-cervical spine instability.

Atlantoaxial dislocation treated by posterior atlantoaxial lateral mass interarticular release,posterior screw reduction and fusion with bone graft / 中国组织工程研究

BACKGROUND:Atlantoaxial dislocation is often facilitated by interlaminar bone grafting.However,there are relatively few reports on the treatment of complex atlantoaxial dislocation with posterior atlantoaxial lateral mass interarticular release and fusion. OBJECTIVE:To explore the safety and effectiveness of atlantoaxial dislocation treated by simple posterior atlantoaxial lateral block interarticular release and fusion. METHODS:We retrospectively analyzed the clinical data of 30 patients with atlantoaxial dislocation who were treated from January 2017 to July 2021,all of whom suffered from reducible atlantoaxial dislocation.Posterior atlantoaxial lateral mass interarticular release and fusion were performed in all patients.During the surgery,patented instruments were used to release the atlantoaxial lateral mass joint,and posterior screw reduction and fixation were used with bone grafting in the lateral mass joint space.The postoperative follow-up period was 6 to 24 months,mean(13.0±5.4)months.During the follow-up period,cervical MRI was reviewed to observe the decompression of the upper cervical spine.X-ray films and CT scans were reviewed to observe the reduction of the upper cervical spine,as well as the internal fixation for looseness and breakage.CT scans were reviewed to assess interlateral block implant fusion.The Japanese Orthopaedic Association score was used to evaluate the improvement of spinal cord function.The neck disability index and the quality of life scale were used to assess the improvement of daily life function.The atlanto-anterior interspace and atlanto-planar spinal effective space were used to evaluate atlantoaxial repositioning and decompression. RESULTS AND CONCLUSION:(1)The surgery of 30 patients went smoothly,and no serious complications such as spinal nerve and vertebral artery injuries occurred during the operation.Postoperative review of cervical MRI showed that the spinal cord compression was lifted.X-ray film and CT showed that the atlanto-anterior gap was significantly reduced;the effective space of atlantoaxial spinal cord was significantly increased,and neurological dysfunctional symptoms were significantly reduced.(2)During the follow-up period,X-ray film and CT showed that the internal fixation was solid;no broken nails or rods occurred,and there was no recurrence of atlantoaxial dislocation.(3)The Japanese Orthopaedic Association scores,neck disability index,and quality of life scores were significantly improved at the last follow-up compared with the preoperative period(P<0.05).The average improvement rate of Japanese Orthopaedic Association scores at the last follow-up was 73.1%.The average neck disability index was 8.80%.All of the patients had a continuous bone-scalp connection between atlantoaxial lateral block joints to achieve osseous fusion.(4)These findings indicate that the use of simple posterior atlantoaxial lateral block interarticular release and fusion for the treatment of atlantoaxial dislocation can significantly increase the fusion rate and shorten the fusion time.

Robot-assisted pedicle screw internal fixation in treatment of atlantoaxial dislocation / 中国组织工程研究

BACKGROUND:Atlantoaxial dislocation,because of its high difficulty and high risk of surgery,has been regarded as the"surgical restricted area"by the international orthopedic community.However,with the rapid development of intelligent digitization in orthopedics,robot-assisted navigation screw placement technology has been widely used in clinical practice,which significantly reduces the difficulty and risk of surgery and improves the safety of surgery.However,there are few reports on the application of this technique in the treatment of atlantoaxial dislocation. OBJECTIVE:To explore the application value of robot-assisted pedicle screw internal fixation in the treatment of atlantoaxial dislocation. METHODS:The medical records of five patients with atlantoaxial dislocation treated with C1-C2 pedicle screw fixation under robot-assisted navigation in Zhuhai Hospital of Guangdong Provincial Hospital of Chinese Medicine from October 2021 to July 2022 were retrospectively analyzed.Operation time,length of neck incision,blood loss,postoperative drainage volume,and length of hospital stay were recorded.Attention should be paid to cerebrospinal fluid leakage,vertebral artery injury,nerve injury,operative area infection and other complications.The visual analog scale score of neck pain,the spinal cord injury grade of the American Spinal Injury Association,the cervical spine score of the Japanese Orthopaedic Association,and the imaging indicators were collected before surgery and at the last follow-up.Screw placement accuracy was assessed. RESULTS AND CONCLUSION:(1)Five patients were successfully completed surgery,without vascular,nerve injury or other complications,and were followed up for 12-20 months.(2)A total of 20 cervical pedicle screws were placed in 5 patients,including 9 type A screws,10 type B screws,and 1 type C screw.The accuracy of screw placement was 95%.(3)At the last follow-up,the visual analog scale score was(0.80±0.71)points,which was significantly lower than that before operation(4.00±2.83)points;the Japanese Orthopaedic Association score was(14.80±0.84)points,which was significantly higher than that before operation(8.00±0.71)points.Anterior atlantodental interval decreased from(7.86±3.25)mm to(2.82±0.93)mm;space available of the spinal cord increased from(6.74±1.99)mm to(12.10±3.51)mm;cervicomedullary angle increased from(133.32±13.55)° to(153.44±9.53)°;clivus-canal angle increased from(128.02±9.92)° to(143.25±12.99)°.The results of the last follow-up indexes were improved compared with those before operation,and the differences were significant(all P<0.05).(4)Postoperative imaging follow-up showed that all patients had bone fusion in the bone graft area,and no internal fixation loosening,fracture or pull-out occurred.(5)This method can avoid relying on the doctor's experience and hand feeling,ensure the accuracy of upper cervical screw placement,reduce the risk of surgery,and obtain satisfactory results in mid-term follow-up.

Long-term efficacy of self-designed posterior atlas polyaxial screw-plate in the treatment of unstable atlas fracture / 中华创伤杂志

Objective:To investigate the long-term efficacy of self-designed posterior atlas polyaxial screw-plate in the treatment of unstable atlas fracture.Methods:A retrospective case series study was conducted to analyze the clinical data of 20 patients with unstable atlas fracture who were admitted to Affiliated Honghui Hospital of Xi′an Jiaotong University from January 2011 to April 2013, including 14 males and 6 females, aged 23-60 years [(42.7±8.6)years]. All the patients were treated with internal fixation using self-designed posterior atlas polyaxial screw-plate. The operation time and intraoperative bleeding volume were recorded. The fracture reduction was evaluated by CT scan at 3 days after surgery. The bone healing was observed by X-ray (anterior-posterior and lateral views of the cervical spine) and CT scan at 9 months after surgery. The delayed spinal cord injuries were evaluated by Frankel grade at 1 and 2 years after surgery and at the last follow-up. The Visual Analogue Scale (VAS) before surgery, at 3 months, 1 year, 2 years after surgery and at the last follow-up were compared. The axial rotation, flexion and extension range of the cervical spine at 3 months, 1 year, 2 years after surgery and at the last follow-up were compared. Intraoperative and postoperative complications were observed.Results:All the patients were followed up for 121-148 months [(135.0±6.8)months]. The operation duration was 68-122 minutes [(86.0±14.1)minutes], with the intraoperative blood loss of 90-400 ml [(120.0±67.9)ml]. The CT scan of the cervical spine at 3 days after surgery showed all satisfactory fracture reduction. Satisfactory bone reunion was observed at 9 months after surgery. All patients were scaled as Frankel grade E at 1 year, 2 years and at the last follow-up after surgery, with no delayed spinal cord injuries observed. The VAS scores of the cervical spine at 3 months, 1 year, 2 years after surgery and at the last follow-up were 2.0(1.3, 3.0)points, 1.0(1.0, 1.8)points, 1.0(0.3, 1.0)points and 1.0(0.3, 1.0)points, which were significantly lower than that before surgery [7.0(6.0, 7.8)points] ( P<0.05), with significantly lower scores at 1-, 2-year after surgeny and at the last follow-up than at 3 months after surgery ( P<0.05). There were no significant differences among the other time points ( P>0.05). The axial rotation ranges of the cervical spine were (103.0±8.3)°, (128.3± 11.4)° and (129.8±13.6)° at 1 year, 2 years after surgery and at the last follow-up respectively, which were significantly higher than that at 3 months after surgery [(85.3±7.0)°] ( P<0.05); It was further improved at 2 years after surgery and at the last follow-up compared with that at 1 year after surgery ( P<0.05), with no significant difference at the last follow-up compared with that at 2 years after surgery ( P>0.05). The flexion and extension range of the cervical spine at 1 year, 2 years after surgery and at the last follow-up were (65.5±4.8)°, (78.3±6.5)° and (79.3±6.9)° respectively, which were significantly higher than that at 3 months after surgery [(54.3±4.4)°] ( P<0.05); It was further improved at 2 years after surgery and at the last follow-up compared with that at 1 year after surgery ( P<0.05), with no significant difference between the last follow-up and 2 years after surgery ( P>0.05). No intraoperative injuries such as arteriovenous injury were observed. No incision infection or dehiscence occurred after surgery, with no complications caused by long-term bed rest such as lung or urinary tract infection, pressure sore formation or deep vein thrombosis occurred. No loosening or breakage of the screw and atlas plate was observed at the long-term follow-up. One patient had mild cervical pain, snap during rotation, and limited range of motion at the last follow-up. Conclusion:Self-designed posterior atlas polyaxial screw-plate has merits including small surgical wounds, satisfactory reduction, solid fixation, obvious pain relief, effective preservation of the previous cervical motion, few complications, and satisfactory long-term efficacy in the treatment of unstable atlas fracture.

Asimilación atlantoidea: malformación, compensación o deformidad. ¿Es parte de la invaginación basilar? / Atlantoid assimilation: malformation, compensation or deformity. Is it part of basilar invagination?

Resumen: Introducción: la asimilación atlantoidea puede presentarse sola o asociada a otras malformaciones y deformidades de la unión craneocervical, los mecanismos etiológicos y patológicos no están esclarecidos. Presentación de caso: paciente de la sexta década de vida, quien fue atendida en el Hospital de Especialidades «Eugenio Espejo¼, con datos clínicos piramidales asimétricos, posteriores a mecanismo de lesión de caída con cinética de baja energía. La sintomatología revirtió con manejo conservador. En la actualidad, la paciente está bajo observación periódica. Conclusión: la asimilación atlantoidea es una malformación congénita muchas veces asintomática y parte de una compensación embriológica cuando está asociada a otras malformaciones. Es necesaria la aparición de deformidad para llegar a la inestabilidad atlantoaxoidea que no es temprana. El conocimiento y poder diferenciar los conceptos de las anormalidades de la unión craneocervical permiten indicar el mejor tratamiento y así obtener los resultados más adecuados con la individualización de cada caso.

Abstract: Introduction: atlas assimilation can occur alone or in association with other craniocervical junction malformations and deformities. The etiological and pathological mechanisms are not clear. Case presentation: patient in her sixth decade of life, who was treated at the «Eugenio Espejo¼ Hospital, with asymmetric pyramidal symptoms after a low-energy kinetic fall. The condition completely reverted with conservative management. The patient is currently under periodic observation. Conclusion: the atlas assimilation, a congenital malformation, often asymptomatic; it is part of an embryological compensation when it is associated with other malformations. The appearance of deformity is necessary to reach atlantoaxial instability that it is not early. The knowledge of the concepts and distinction of the craniocervical junction abnormalities allows to indicate the best treatment in order to obtain the most suitable results with the individualization of each case.

Posterior Atlantoaxial Screw Placement in a Portuguese Population: A Morphometric Analysis Based on Computed Tomography Scan Measurements / Colocação de parafusos atlantoaxiais posteriores em uma população portuguesa: Uma análise morfométrica baseada em medidas de tomografia computadorizada

Abstract Objective The present study aims to evaluate the screw length and trajectory angles for posterior atlantoaxial fixation in a Portuguese population, through the study of cervical computed tomography (CT) scans. Methods Cervical CT scans of 50 adults were measured according to predefined screw trajectories of C1-C2 transarticular (C1C2TA), C1 lateral mass (C1LM), C2 pedicle (C2P), C2 pars and C2 laminar (C2L) screws. For each of these trajectories, screw length and angles were measured and compared between males and females. Results For the C1C2TA screw trajectory, the mean length, medial, and cranial angles were 34.12 ± 3.19 mm, 6.24° ± 3.06, and 59.25° ± 5.68, respectively, and for the C1LM screw trajectory, they were 27.12 ± 2.15 mm, 15.82° ± 5.07, and 13.53° ± 4.80, respectively. The mean length, medial, and cranial angles for the C2P screw trajectory were 23.44 ± 2.49 mm, 27.40° ± 4.88, and 30.41° ± 7.27, respectively; and for the C2 pars screw trajectory, they were 16.84 ± 2.08 mm, 20.09° ± 6.83, and 47.53° ± 6,97. The mean length, lateral, and cranial angles for the C2L screw trajectory were 29.10 ± 2.48 mm, 49.80° ± 4.71, and 21.56° ± 7.76, respectively. There were no gender differences except for the lengths of the C1C2TA (p= 0,020) and C2L (p= 0,001) screws, which were greater in males than in females. Conclusion The present study provides anatomical references for the posterior atlantoaxial fixation in a Portuguese population. These detailed data are essential to aid spine surgeons to achieve safe and effective screw placement.

Resumo Objetivo O presente estudo tem como objetivo avaliar o comprimento e os ângulos de trajetória do parafuso para fixação atlantoaxial posterior em uma população portuguesa por meio do estudo de tomografia computadorizada (TC) cervical. Métodos Tomografias computadorizadas cervicais de 50 adultos foram analisadas quanto às trajetórias pré-definidas dos parafusos transarticulares C1-C2 (C1C2TA), na massa lateral de C1 (C1LM), no pedículo de C2 (C2P) e na pars de C2 e C2 laminar (C2L). O comprimento e os ângulos dos parafusos em cada uma destas trajetórias foram medidos e comparados entre homens e mulheres. Resultados O comprimento médio e ângulos medial e cranial da trajetória do parafuso C1C2TA foram de 34,12 ± 3,19 mm, 6,24° ± 3,06 e 59,25° ± 5,68, respectivamente; as medidas da trajetória do parafuso C1LM foram 27,12 ± 2,15 mm, 15,82° ± 5,07 e 13,53° ± 4,80. O comprimento médio e os ângulos medial e cranial da trajetória do parafuso C2P foram de 23,44 ± 2,49 mm, 27,40° ± 4,88 e 30,41° ± 7,27, respectivamente; as medidas da trajetória do parafuso da pars de C2 foram 16,84 ± 2,08 mm, 20,09° ± 6,83 e 47,53° ± 6,97. O comprimento médio e ângulos lateral e cranial da trajetória do parafuso C2L foram de 29,10 ± 2,48 mm, 49,80° ± 4,71 e 21,56° ± 7,76, respectivamente. Não houve diferenças entre os gêneros, à exceção do comprimento dos parafusos C1C2TA (p= 0,020) e C2L (p= 0,001), que foi maior no sexo masculino do que no feminino. Conclusão O presente estudo fornece referências anatômicas para a fixação atlantoaxial posterior em uma população portuguesa. Estes dados detalhados são essenciais para ajudar os cirurgiões de coluna a colocar os parafusos de maneira segura e eficaz.

The Short-term Effectiveness of Three Manipulations for Atlantoaxial Joint Disorders and the Effects on Surface Electromyography of Sternocleidomastoid Muscle / 中医杂志

ObjectiveTo compare the short-term effectiveness of the three different manipulations for atlantoaxial joint disorders and their effects on surface electromyography of sternocleidomastoid muscle. MethodsNinty patients with atlantoaxial joint disorders were randomly divided into the tendon relaxing manipulation group， the tendon relaxing plus rehabilitation manipulation group， and the conventional manipulation group， with 30 cases in each group， and each group of patients received the corresponding manipulation treatment for 2 weeks. The changes of visual analogue score （VAS） of occipital neck pain， evaluation scale for cervical vertigo （ESCV）， and averaged electromyography （AEMG） of surface electromyography of bilateral sternocleidomastoid muscles before and after the treatment were observed， and the clinical effectiveness and safety of the patients were compared among groups. ResultsThe VAS scores of patients in each group decreased， and the ESCV scores increased after treatment （P＜0.01）， and the tendon relaxing manipulation group and the tendon relaxing plus rehabilitation manipulation group were significantly better than the conventional manipulation group （P＜0.01）. The AEMG of the bilateral sternocleidomastoid muscles of the three groups increased after treatment （P＜0.01）； when compared among the three groups， the AEMG of the bilateral sternocleidomastoid muscles of the tendon relaxing plus rehabilitation manipulation group was higher than that of the tendon relaxing manipulation group， and the tendon relaxing manipulation group was higher than that of the conventional manipulation group （P＜0.05 or P＜0.01）. The cure and markedly effective rates of the tendon relaxing manipulation group， the tendon relaxing plus rehabilitation manipulation group， and the conventional manipulation group were 56.67%， 86.67%， and 36.67% respectively， showing statistically difference （K=10.21， P＜0.01）. ConclusionThe tendon relaxing manipulation and tendon relaxing plus rehabilitation manipulation can effectively improve the symptoms of vertigo， headache， and neck pain for patients with atlantoaxial joint disorders， and can improve the contraction function of sternocleidomastoid muscle， whose effectiveness are better than that of conventional manipulation.

Biomechanical Study on Atlantoaxial Dislocation Combined with Basilar Invagination by Different Posterior Internal Fixation Methods / 医用生物力学

Objective To investigate biomechanical differences of two posterior occipitocervical internal fixation techniques for treating basilar invagination with atlantoaxial dislocation (BI-AAD). Methods Intra-articular cage + posterior occipital plate+C2 pedicle screw (Cage+C2PS+OP), and intra-articular cage+C1 lateral mass screw+C2PS (Cage+C1LMS+C2PS) models were established based on occipitocervical CT data of the BI-AAD and clinical operation scheme, and the stability of atlantoaxial joint and stress distribution characteristics of C2 endplate and implanted instruments under different motion states were analyzed. Results Compared with the Cage+C1LMS+C2PS model, the atlantoaxial range of motion ( ROM) under flexion, extension, lateral bending and axial rotation in the Cage+C2PS+OP model were reduced by 5. 26% , 33. 33% , 43. 75% , -5. 56% , and stress peak of screw-rod fixation system were reduced by 47. 81% , 60. 90% , 48. 45% , 39. 14% , respectively. Under two internal fixation modes, stresses of C2 endplate and cage were mainly distributed on the compressive side during the motion, and both the screw-bone interface and the caudal side of screw subjected to large loading. Conclusions Two internal fixation methods could provide similar stability. However, the stress concentration of screw-rod system was more obvious and the possibility of screw loosening and fracture was greater under Cage+ C1LMS+C2PS fixation.

Research Progress on the Application of Goel Technique in Craniovertebral Junction Anomalies / 中国医学科学院学报

Craniovertebral junction anomalies are a group of diseases characterized by the pathological changes of occipital bone,atlantoaxial bone,cerebellar tonsil,surrounding soft tissue,and nervous system,which are caused by a variety of factors.Chiari malformation is a common type of craniovertebral junction anomalies,the conventional surgical therapy of which is posterior fossa decompression.Currently,scholars represented by Goel have proposed a new theory on the classification,pathogenesis,and treatment of Chiari malformation based on posterior atlantoaxial fixation (Goel technique).This article introduces the progress in Goel technique,aiming to provide reference for the clinical work.

3D-printed navigation template-assisted and freehand posterior cervical screw fixation of atlantoaxial fracture: a comparison of efficacies / 中华创伤杂志

Objective:To compare the efficacies of 3D-printed navigation template assisted and freehand posterior cervical screw fixation of atlantoaxial fractures.Methods:A retrospective cohort study was used to analyze the clinical data of 22 patients with atlantoaxial fractures admitted to Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from September 2018 to December 2020. There were 13 males and 9 females, with age range of 26-68 years [(50.7±11.9)years]. All the patients underwent posterior atlantoaxial pedicle screw internal fixation and fusion, among whom 11 patients admitted from November 2019 to December 2020 were assisted with 3D printed navigation templates for the placement of pedicle screws (assisted group) and 11 patients admitted from September 2018 to October 2019 used the traditional way of placing pedicle screws (freehand group). A total of 88 pedicle screws were implanted, with 44 pedicle screws in each group. The operation time, intraoperative blood loss, and intraoperative fluoroscopy frequency were compared between the two groups. The visual analogue score (VAS) and Japanese Orthopedic Society (JOA) score were also compared before operation, at 3 days, 3 months, 6 months postoperatively and at the last follow-up. The accuracy of pedicle screw placement was evaluated according to the Kawaguchi classification, and complications were observed.Results:All the patients were followed up for 24-30 months [(26.4±1.8)months]. The assisted group showed the operation time of (87.3±19.5)minutes and the intraoperative fluoroscopy frequency of (6.4±1.4)times, decreased compared with the freehand group [(115.5±23.0)minutes, (10.3±1.7)times] [(all P<0.01). However, no significant difference was observed in the intraoperative blood loss between the two groups ( P>0.05). Both groups demonstrated comparable VAS and JOA score before operation, at 3 days, 3 months, 6 months postoperatively and at the last follow-up (all P>0.05). Furthermore, the assisted group exhibited a significantly higher accuracy of pedicle screw placement [95.5% (42/44)] compared with the freehand group [79.5% (35/44)] ( P<0.05). Notably, there were no intraoperative vertebral artery injury, spinal cord injury, or cerebrospinal fluid leakage in either group, or internal fixation loosening, fracture, nonunion in either group after operation. Conclusion:Compared with freehand posterior cervical screw placement, 3D-printed navigation template-assisted posterior cervical pedicle screw fixation of atlantoaxial fracture can shorten the operation time, reduce the intraoperative fluoroscopy frequency, and improve the accuracy of screw placement.

O-arm navigation system-assisted upper cervical pedicle screw internal fixation for traumatic atlantoaxial instability / 中华创伤杂志

Objective:To explore the efficacy of O-arm navigation system-assisted upper cervical pedicle screw internal fixation in the treatment of traumatic atlantoaxial instability.Methods:A retrospective cohort study was conducted to analyze the clinical data of 61 patients with atlantoaxial instability admitted to Affiliated Honghui Hospital of Xi′an Jiaotong University from January 2021 to June 2022, including 34 males and 27 females, aged 20-77 years [(50.2±13.1)years]. A total of 38 patients were treated with unarmed screw placement (unarmed group), and 23 with O-arm navigation system-assisted screw placement (navigation group). The unarmed group was divided into experienced group ( n=20) and unexperienced group ( n=18) based on the surgeons′ experience (whether they had 20 years or longer experience of spinal surgery and performed more than 100 atlantoaxial surgeries independently). The screw placement and surgical time of each group was recorded. The cervical CT scan was conducted at 7 days after surgery to evaluate the satisfaction rate of pedicle screw placement and cortical penetration rate according to Neo grading criteria. The cervical nerve function of the patients before, at 7 days after surgery and at the last follow-up was evaluated using the Japanese Orthopedic Association (JOA) score and the Neck Disability Index (NDI). The occurrence of complications was observed. Results:All patients were followed up for 9-25 months [(16.3±4.2)months]. There were no statistically significant differences in the screw placement and surgical time between the navigation group and the unarmed group (all P>0.05). The screw placement time of the navigation group was (41.0±7.8)minutes, longer than that of the experienced group [(23.6±6.8)minutes] ( P<0.01) and shorter than that of the unexperienced group [(50.1±10.1)minutes] ( P<0.05). The surgical time of the navigation group was (101.9±9.9)minutes, which was longer than that of the experienced group [(67.6±8.3)minutes] ( P<0.01) and shorter than that of the unexperienced group [(126.1±16.4)minutes] ( P<0.01). The satisfaction rate of pedicle screw placement and cortical penetration rate of the navigation group were 98.9% and 4.3%, respectively, which were better than those of the unarmed group (94.1% and 17.8%), the experienced group (96.2% and 13.8%), and the unexperienced group (91.7% and 22.2%) ( P<0.05 or 0.01). There was no statistically significant difference in JOA score or NDI before, at 7 days after surgery or at the last follow-up between the navigation group and the unarmed group, and no difference between the navigation group and the experienced group or the unexperienced group (all P>0.05). No complications such as spinal cord nervous or vascular injuries were observed during surgery in the navigation group or the unarmed group. Conclusions:Compared with the unarmed screw placement, O-arm navigation system-assisted upper cervical pedicle screw internal fixation shows no significant difference in screw placement time, surgical time, and postoperative neurological function status in the treatment of traumatic atlantoaxial instability, but has a higher accuracy in screw placement. Compared with the experienced surgeons′ unarmed screw placement, the technique also has higher screw placement accuracy but longer screw placement time and surgical time. Whereas in comparison with unexperienced surgeons′ unarmed screw placement, the technique can not only significantly improve its screw placement accuracy, while shortening screw placement time and surgical time so as to improve the surgical safety.

Posterior atlantoaxial non-fusion fixation versus anterior cervical odontoid screw fixation in treatment of odontoid fracture of Anderson-D'Alonzo type Ⅱ / 中华创伤骨科杂志

Objective:To compare the curative effects of posterior atlantoaxial non-fusion fixation and anterior cervical odontoid screw fixation in the treatment of odontoid fracture of Anderson-D'Alonzo type Ⅱ.Methods:A retrospective study was conducted to analyze the clinical data of 21 patients with odontoid type II fracture who had been treated at Department of Spine Surgery, The Central Hospital of Luohe from January, 2015 to January, 2020. The patients were divided into a posterior group subjected to posterior atlantoaxial non-fusion fixation and an anterior group subjected to anterior cervical odontoid screw fixation. In the posterior group of 12 patients, there were 7 males and 5 females with an age of (42.2±11.8) years. In the anterior group of 9 patients, there were 5 males and 4 females with an age of (40.0±9.1) years. The 2 groups were compared in terms of operation time, bleeding volume, intraoperative fluoroscopy, fusion time, cervical rotation and neck dysfunction index (NDI).Results:The differences in the preoperative general information were not statistically significant between the 2 groups, indicating comparability ( P>0.05). The implants were successfully inserted in all patients. Intraoperative fracture reduction was satisfactory and no arteriovenous or spinal cord injuries occurred. The mean follow-up time was (24.5±11.3) months. The operation time [(108.5±15.9) min] and bleeding volume [(48.3±12.2) mL] in the anterior group were significantly less than those in the posterior group [(153.9±34.2) min and (275.8±56.0) mL], and the intraoperative fluoroscopy [(13.0±2.1) times] in the anterior group was significantly higher than that in the posterior group [(7.2±1.4) times] ( P<0.05). There was no statistically significant difference in fracture healing time between the 2 groups ( P>0.05). There was no statistically significant difference either in total cervical rotation or NDI between the 2 groups at the last follow-up ( P>0.05). Conclusions:Posterior atlantoaxial non-fusion fixation can preserve the range of rotation of the cervical spine and reduce the dysfunction of the cervical spine. The anterior screw fixation may result in shorter operation time and less intraoperative bleeding, but more intraoperative X-ray fluoroscopy. Therefore, the 2 internal fixation methods should be adopted on the basis of each individual in the treatment of odontoid type Ⅱ fracture to achieve good curative results.

Preliminary application of self-designed posterior reduction forceps for atlantoaxial dislocation in treatment of irreducible atlantoaxial dislocation / 中华创伤骨科杂志

Objective:To evaluate the preliminary clinical application of our self-designed posterior reduction forceps for atlantoaxial dislocation in the reduction and fixation of irreducible atlantoaxial dislocation with simple posterior screw-rod system.Methods:Our posterior reduction forceps was self-designed and developed to assist simple posterior screw-rod system in the treatment of irreducible atlantoaxial dislocation based on the posterior atlantoaxial screw-rod system. A retrospective study was conducted to analyze the clinical data of 5 patients with irreducible atlantoaxial dislocation who had been treated from January 2021 to October 2022 at Department of Spine Surgery, General Hospital of Southern Theatre Command of PLA with our self-designed posterior reduction forceps. There were 2 males and 3 females, aged 53, 62, 45, 32 and 48 years, respectively. Diagnosis: 1 case of free odontoid process combined with atlantoaxial dislocation, 2 cases of atlantoaxial dislocation, and 2 cases of old odontoid process fracture combined with atlantoaxial dislocation. Respectively, their preoperative Japanese Orthopaedic Association (JOA) scores were 9, 11, 12, 13 and 10 points and their atlanto-dental intervals (ADI) 9.8, 7.4, 6.6, 6.4 and 8.5 mm. Postoperatively, atlantoaxial reduction and spinal cord compression were evaluated by X-ray, CT, and MRI examinations, and internal fixation, atlanto-axial sequence, and bone graft fusion by X-ray and CT examinations. One week after surgery, the JOA scores were used to evaluate the patients' neurological function and the ADI was measured to evaluate the atlantoaxial reduction.Results:The surgery was successfully performed in the 5 patients, with no intraoperative complications like neurovascular injuries to the spinal cord. The postoperative atlantoaxial reduction was satisfactory, the position of internal fixation was good, the compression to the spinal cord was relieved, and the clinical symptoms were significantly improved. At 1 week after surgery, respectively, the JOA score: 13, 14, 14, 15 and 13; the ADI: 2.6, 2.1, 1.8, 1.5 and 2.2 mm; the follow-up time: 3, 6, 12, 9 and 6 months; the bone fusion time: 3, 3, 6, 6 and 3 months. Follow-ups revealed no loosening or fracture of internal fixation, good atlanto-axial sequence, and no recurrence of dislocation.Conclusion:Our self-designed posterior reduction forceps for atlantoaxial dislocation can assist the simple posterior screw-rod system to treat irreducible atlantoaxial dislocation, leading to good preliminary clinical outcomes.

Efficacy evaluation of cluster nursing in robot-assisted surgery for the treatment of reducible atlantoaxial dislocation / 中华创伤杂志

Objective:To explore the effect of cluster nursing in robot-assisted surgery for the treatment of reducible atlantoaxial dislocation.Methods:A retrospective cohort study was conducted to analyze the clinical data of 41 patients with reducible atlantoaxial dislocation treated by robot-assisted surgery in Honghui Hospital affiliated to Xi′an Jiaotong University from January 2019 to December 2021, including 28 males and 13 females; aged 18-79 years [(45.2±10.3)years]. Ninteen patients received cluster nursing (cluster nursing group), with operating room nursing team set up on the basis of routine nursing and performed cluster nursing in line with evidence-based medicine. Twenty-two patients received routine nursing (routine nursing group). The operation time, intraoperative blood loss, frequency of intraoperative C-arm fluoroscopy, time of drainage tube placement and chief surgeon′s satisfaction for nursing were compared between the two groups. The degree of pain was evaluated by pain numerical score (NRS) at 12 hours, 24 hours, 48 hours, 72 hours, 1 month and 3 months after operation and at the last follow-up. The neck disability index (NDI) was assessed at 1 day before operation, 1 month after operation, 3 months after operation and at the last follow-up. The complications were observed.Results:All patients were followed up for 12-18 months [(16.7±3.7)months]. The operation time, intraoperative blood loss, frequency of C-arm fluoroscopy and time of drainage tube placement in cluster nursing group were (82.9±10.4)minutes, (105.9±11.8)ml, (3.8±0.6)times and (1.5±0.4)days, while those in routine nursing group were (125.7±12.8)minutes, (208.4±13.8)ml, (9.7±2.3)times and (3.6±0.6)days, respectively (all P<0.01). The chief surgeon′s satisfaction for nursing was 94.7% (18/19) in cluster nursing group and was 68.2% (15/22) in routine nursing group ( P<0.05). The NRS in cluster nursing group was (6.2±0.4)points, (6.0±0.7)points, (4.9±1.1)points, (2.7±0.5)points, (1.9±0.4)points, (1.8±0.4)points and (1.5±0.3)points at 12 hours, 24 hours, 48 hours, 72 hours, 1 month and 3 months after operation and at the last follow-up, while it was (7.6±0.6)points, (6.8±1.2)points, (5.8±1.5)points, (4.2±0.8)points, (3.4±0.7)points, (2.6±0.5)points and (2.2±0.5)points in routine nursing group ( P<0.05 or 0.01). There was no significant difference in the NDI between the two groups at 1 day before operation, but the NDI in cluster nursing group was 20.6±4.5, 14.6±2.8 and 10.7±2.5 at 1 month and 3 months after operation and at the last follow-up, while it was 26.9±4.1, 18.7±3.3 and 13.7±1.7 in routine nursing group (all P<0.01). There was no hematoma, infection or implant-related complications in both groups .Conclusion:For robot-assisted surgery in the treatment of reducible atlantoaxial dislocation, cluster nursing is associated with shortened operation time and time of drainage tube placement, decreased intraoperative blood loss and frequency of intraoperative fluoroscopy, increased chief surgeon′s satisfaction for nursing, reduced pain and accelerated functional recovery.

Study on radiation dose and image quality differences between cone-beam CT and multi-slice spiral CT for atlantoaxial spine imaging / 中华放射医学与防护杂志

Objective:To compare the differences in radiation dose and image quality between cone-beam CT (CBCT) and multi-slice spiral CT (MSCT) applied to atlantoaxial spine imaging.Methods:Head and neck phantom was scanned at 30 exposure parameter combinations using Pramerica CBCT scanner and 15 parameter combinations using Toshiba 320-row MSCT. The effective dose ( E) of CBCT was calculated based on the Monte Carlo dose estimation software PCXMC, the E value of MSCT was obtained by multiplying the dose length product (DLP) by the related factor. t-test for two independent samples or Wilcoxon rank sum test were used for comparison of radiation dose and subjective and objective image quality between two modalities. The subjective evaluation was a 5-point subjective scale using double-blind method for edge sharpness, contrast, soft tissue level, and artifacts of the images. The signal and noise in the region of interest (ROI) were measured and the contrast signal-to-noise ratio (CNR) was calculated. Results:For radiation dose, the volumetric dose index and E values of 2.9 mGy and 27.61 μSv for CBCT were lower than those of 8.8 mGy and 433.16 μSv for MSCT, and the differences were statistically significant( z=-3.05, -5.25, P<0.05). For objective evaluation of image quality, the noise and CNR were 27.74 HU and 3.69 in CBCT group, 7.84 HU and 27.1 in MSCT group. The difference between them were statistically significant( z=-5.39, -5.42, P<0.05). The overall image quality, contrast and artifact scores of the CBCT group were 3.5, 3.0 and 5 were higher than those of the MSCT group at 2.0, 2.0, and 4.0, respectively ( z=-2.32, -2.46, -3.31, P<0.05). Conclusions:Both atlantoaxial CBCT and MSCT scans provide image quality that meets diagnostic requirements. Compared to MSCT, CBCT atlantoaxial scans can effectively reduce radiation dose according to the principle of optimization of radiation protection.

Research progress of Chiari malformation type I and atlantoaxial instability / 中华骨科杂志

Chiari malformation (CM) is a group of congenital cerebellar tonsillar hernia malformations involving the craniocervical junction. Chiari malformation type I (CMI) is the most common in clinic, however its pathogenesis is still unclear, and there is no consensus on the surgical treatment standard of CMI. At present, the most widely accepted is the theory of posterior fossa incompatibility, so doctors at home and abroad use posterior fossa decompression (PFD) and posterior fossa compression with duraplasty (PFDD) as the gold standard for surgical treatment, and have their own experience and technical improvement. However, the volume of the posterior cranial fossa in some patients is no different from that in healthy people, and about 30% of the patients with CMI have poor results after posterior cranial fossa decompression. As a result, this operation cannot treat all patients with CMI. In recent years, with the development of imaging, the progress of diagnostic technology and the deepening of understanding of CM, some studies have shown that CMI may be related to atlantoaxial instability, and proposed that CMI is the secondary factor of atlantoaxial instability, and atlantoaxial fusion is the standard of surgical treatment, which has caused great controversy in academic circles. Different clinical research results of scholars support or oppose this theory: some studies have shown that the clinical symptom relief rate of patients with CMI treated with atlantoaxial fusion is 96.9%; another study showed that 70% of patients with CMI underwent atlantoaxial fusion had improved neurological function, but the overall postoperative effect was not satisfactory. In short, CMI is related to many diseases and its clinical manifestations are complex. Therefore, individualized management and treatment should be carried out in combination with the clinical manifestations and auxiliary examination results of patients.

Axial instrument strategy for atlantoaxial dislocation with complex artery variation / 中华骨科杂志

Objective:To evaluate the axial instrument strategy for atlantoaxial dislocation with complex vertebral artery variation.Methods:A total of 55 patients with atlantoaxial dislocation who underwent surgical treatment from January 2019 to December 2021 were retrospectively analyzed, including 14 males and 41 females, aged 54.0±12.8 years (range, 22-78 years). Among these patients, 10 patients with unilateral vertebral artery high ride with contralateral vertebral artery occlusion, 30 patients with bilateral vertebral artery high ride with single dominant vertebral artery, 15 patients with bilateral vertebral artery high ride. All patients underwent posterior reduction and internal fixation. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the postoperative efficacy.Results:All patients completed the surgery successfully with a follow-up time of 14.6±5.5 months (range, 6-24 months). C 2 pedicle screw fixation was performed on the non-dominant side of unilateral vertebral artery high ride and the non-dominant side of bilateral vertebral artery high ride with one dominant vertebral artery (40 vertebraes). The dominant side of unilateral high vertebral artery and bilateral high vertebral artery with one dominant vertebral artery was fixed with C 2 medial "in-out-in" screw (10 vertebraes), C 2 isthmus screw (21 vertebraes), C 2 without screw (9 vertebraes) only extended the fixed segment. For bilateral vertebral artery high ride patients, one side was used C 2 "in-out-in" pedicle screws (right 10 vertebraes, left 5 vertebraes), and the other side was fixed with C 2 medial "in-out-in" screw (8 vertebraes), C 2 isthmus screw (5 vertebraes), C 2 without screw only extended the fixed segment (2 vertebraes). The JOA scores were 8.5±1.8, 13.9±1.3, and 14.4±1.1 preoperatively, 6 months postoperatively, and at the final follow-up, respectively, with statistically significant differences ( F=279.40, P<0.001). JOA at 6 months postoperatively and at the final follow-up was greater than preoperatively, and the differences were statistically significant ( P<0.05), whereas the differences in JOA scores at 6 months postoperatively and at the final follow-up was not statistically significant ( P>0.05). Preoperative, 6 months postoperatively and final follow-up cervical VAS scores were 3.7±1.9, 2.1±0.9 and 1.6±1.0, respectively, with statistically significant differences ( F=39.53, P<0.001). The cervical VAS at 6 months postoperatively and at the last follow-up was less than that before surgery, and the differences were statistically significant ( P<0.05). Cervical VAS scores at 6 months postoperatively were greater than at the last follow-up, with a statistically significant difference ( P<0.05). Conclusion:For patients with atlantoaxial dislocation with complex vertebral artery variation, C 2 lateral "in-out-in" screw, C 2 medial "in-out-in" screw, isthmus screw fixation or C 2 without screw only extended the fixed segment can obtain good clinical efficacy.